Continuous loop suture and button assemblies are commonly used during orthopedic surgery for bone-tendon-bone, single-bundle soft tissue, and double bundle soft tissue fixation, such as during cruciate reconstruction. For example, during anterior cruciate ligament (ACL) reconstruction, a bone-tendon-bone graft is commonly positioned within both the femur and tibia bones. These grafts are often secured to a continuous loop/button assembly, which are in turn anchored to a bone. One example of a loop/button assembly is disclosed in U.S. Pat. No. 6,533,802 to Bojarski et al. (“Bojarksi”). Bojarski references a few different general methods of attaching a button to a continuous loop: (a) start with a closed loop suture and then capture the button by threading loop sections through openings in the button or wrapping the loop sections around channels/arms of the button (e.g., Bojarksi FIG. 12), (b) start with a thread having a leading end and utilize an automated winding machine to continuously wrap the leading end through apertures in the button to form a closed loop, such as disclosed in WO99/47079 to Bryant (“Bryant”), or (c) provide a suture with two open ends, thread and/or wrap the suture to an anchor button and then tie the open ends together, such as disclosed in U.S. Pat. No. 5,769,894 to Ferragamo (“Ferragamo”). The above described methods of making continuous loop and button assemblies result in products that are susceptible to breaking over time due to mechanical stress.
Additionally, U.S. Pat. No. 9,357,990 describes an assembly having a fixed sized loop attached to a button. This has provided a helpful advance in the art.
U.S. Pat. No. 6,517,578 discloses a device similar to those described in the references discussed above, except for that the suture loop that is threaded through the buttonholes has a variable size. To achieve this result a double trap is used with two suture lengths crossing each other inside a lumen in another length of the same suture. This adjustability permits the surgeon using the device to adjust it prior to use, and also to adjust the loop size during surgery. There is an advantage in not having to keep many different sizes of suture loop-button constructs on hand for surgeries on patients with differing bone thicknesses. Unfortunately, during use, the loop tends to expand, due to slippage in the double trap, leading to problems with the ligament implantation. Efforts to create a suture having less slippage by expanding the length of the double trap have met with issues in the construction of the construct.